Final answer:
In reaction to the Israelites' complaints, Moses descended from Mt. Sinai and discovered them worshipping a golden calf, violating the commandment against idolatry. He expressed his anger by breaking the stone tablets that held the Ten Commandments.
Step-by-step explanation:
After the Israelites complained to Moses and Aaron, a significant event occurred the next day that is chronicled in the Old Testament. Moses descended from Mt. Sinai to find the Israelites worshipping a golden calf, an idol they had constructed during his absence. This was a grievous sin as it violated the commandment, "Thou shalt not make any graven images." In his wrath at the sight of this idolatry, Moses threw the stone tablets inscribed with the Ten Commandments, shattering them at the foot of the mountain.
The biblical narrative emphasizes the consequences of disobeying the covenant with God, which was established during the Exodus from Egypt to Canaan, as the Israelites agreed to worship only the single God, Yahweh. Moses's reaction to their apostasy by breaking the tablets highlights the severity of their actions, and serves as a crucial turning point in the relationship between God and the Israelites.